Professional skepticism is an attitude that requires the existence of a questioning mind, the awareness of possible situations containing misstatements resulting from mistake or fraud and finally, the critical evaluation of the audit evidence available. The most important criticism that auditors usually face in financial reporting is the lack proper presentation of professional skepticism. Based on Nelson’s model (2009) of personality traits, this study examines the role of three influential personality traits on auditors’ professional skepticism. The traits include mindset, ethical values, and behavioral deviations. Also, the roles of deliberative mindset and implemental mindset on the application of auditors’ situational professional skepticism in financial reporting are reviewed. Using computer-based test method and structural equation model, the study is conducted among 203 auditors. Results indicate that the more deliberative stage lasts, the higher will be an auditor’s professional skepticism level. Also, by increasing the level of ethical values among auditors and decreasing their behavioral deviations, the level of their professional skepticism increases.